This invention relates to a safety cap for containers containing substances that might pose a danger if consumed by children or persons not having the ability to understand the danger. Such safety caps are sometimes termed "child resistant" caps or "childproof" caps.
A particular object of this invention is to provide a safety cap that has the desired "child resistant" feature, but is nevertheless openable with a relatively small manual effort. The invention accomplishes the "child resistant" feature by concealing the cap actuator from direct view, not by making the actuator difficult to operate.
Some existing safety caps use actuators that include beads or lugs designed to snap over lips or flanges on the container mouth in order to remove the cap from the container. Safety is achieved because the child is physically unable to apply enough force on the actuator to pry the cap off of the container. A problem with such arrangements is that many older persons, especially persons afflicted with arthritis, do not have the manual dexterity to operate the caps.
The present invention contemplates a screw-on cap structure equipped with an add-on locking pin that extends axially into an opening in an annular flange formed on the container. In its normal position the pin acts as an anti-rotation device to prevent the cap from being manually unscrewed from the container. The pin has an accessible free end located underneath the container flange in a partially concealed position. The person can exert finger pressure on the accessible free end of the pin to move the pin to a position partially projecting above the cap; a pulling motion on the projecting portion of the pin moves the pin to a position wherein it does not obstruct turning motion of the cap off of the container.
The locking pin is designed to be partially concealed from view, such that it is not likely to be noticed by a small child. Also, the pin is adapted to be moved with only a relatively small manual force, thereby making it usable by older arthritic persons who may not have a great deal of hand strength or manual dexterity. Additionally, the pin is constructed so that two distinct motions are required to move the pin from its obstruct position to its non-obstruct position, i.e. a push-up motion with the person's finger, and a pulling motion after the outer end of the pin has been projected from the cap surface. This last-mentioned feature makes the cap structure child resistant.